Few areas of the Supreme Court’s jurisprudence have attracted as much attention in recent decades as the case law recognizing a constitutional right to terminate a pregnancy. Justice Anthony M. Kennedy has exercised more influence over the Court’s abortion jurisprudence than perhaps any other sitting Justice. His jointly authored plurality opinion in Planned Parenthood of Southeastern Pa. v. Casey reaffirmed the basic right to an abortion first recognized in Roe v. Wade, applying that right to regulations effective from the outset of pregnancy. Later opinions, particularly Justice Kennedy’s dissent in Stenberg v. Carhart and his majority opinion in Gonzales v. Carhart, have instead focused on regulations applicable to abortions performed in the second trimester of pregnancy or beyond.

Justice Kennedy’s more recent opinions may suggest that we have not heard the last word on state regulation of late-term abortions. The reasoning of Justice Kennedy’s opinions in Stenberg and Gonzales casts doubt on the justification for the dicta in Roe/Casey indicating that the constitutional right to abortion continues until a fetus is “viable,” i.e., able to survive outside the womb with medical assistance. The Court has never offered an adequate constitutional justification for the viability rule, a line that produces arbitrary and irrational results, pushes U.S. law outside the international mainstream and prevents the development of a stable political consensus on regulation of abortion. It remains to be seen what Justice Kennedy will do if a future case requires the Court to squarely address the duration of abortion rights. While his opinions in Stenberg and Gonzales are written so that continued adherence to the viability rule would be possible, they also make clear that Justice Kennedy finds second-trimester abortions troubling and recognizes legitimate grounds for state regulation at that stage of pregnancy.

Justice Kennedy’s opinions leave open at least two paths by which states might be afforded greater flexibility in the regulation of second-trimester abortions. First, Justice Kennedy’s opinion in Gonzales (especially when read in light of his Stenberg dissent) permits states to justify abortion regulations based on novel state interests distinct from the two recognized in Roe (protecting fetal life and maternal health). There is no reason that all of the new state interests permitted under Gonzales would necessarily be governed by the viability rule, which was developed in the context of the particular state interest in protecting potential life.

Second, it may be that the time has come to revisit the viability rule or, more accurately, to finally consider its validity for the first time on the basis of plenary briefing and argument. The viability rule was adopted in dicta in Roe and reaffirmed in dicta in Casey. Consequently, the Court was not forced to grapple with the duration of abortion rights in a case where it mattered to the outcome. The result has been the Court’s longstanding failure to explain why the capacity to survive outside the womb should be required as a constitutional matter before a state can protect the life of a second-trimester fetus. These factors — adoption in dicta, inadequacy of briefing and argument, and failure to offer a convincing rationale — have long been viewed as undercutting the precedential weight of rules announced in prior opinions. Moreover, the pragmatic considerations that persuaded the Casey plurality to retain the right to an abortion cut the opposite direction when applied to the viability rule. For instance, the Court has acknowledged “the uncertainty of the viability determination,” a characteristic that makes viability unworkable as a line to regulate medical practice. Likewise, while some women may place reliance on the availability of abortion in making decisions about relationships and career paths, it is implausible that such decisions place substantial reliance on the viability rule’s extension of abortion rights through most of the second trimester of pregnancy. Consequently, the Court’s decisions surrounding the law of precedent would support reconsideration of the duration of abortion rights in a case that squarely presented the issue.